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D Gordon

Publications and source records attributed to D Gordon.

At least 55 records · Page 3Linked to original sources
PubMed2001

Expression of metalloproteinases and its inhibitor in later stage of rabbit neointima development.

Neointima formation after arterial de-endothelialization refers not only to smooth muscle cell (SMC) migration and proliferation, but also involves extracellular matrix (ECM) metabolism. Most studies regarding the role of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in neointima have focused on the early phase of vascular remodeling. In this study, we examined the expression of MMP and TIMP in rabbit aortic neointima at a relatively late stage of lesion development, between 4 and 12 weeks after initial de-endothelialization. Northern blot analysis revealed expression of steady-state MMP-9 mRNA was increased up to the 4th week and MMP-2 mRNA to the 12th week after de-endothelialization. In situ hybridization shown that MMP positive cells were predominantly distributed in arterial neointima. Expression of TIMP-1 mRNA was continuously up-regulated up to the 12th week and TIMP-1 positive cells, primarily SMCs, were also localized to the neointimal tissue. Alteration at mRNA level was accompanied by that at protein level, as assessed by SDS-PAGE zymography for MMPs and immunoblotting for TIMP-1. The profile of alteration at protein level correlated well with that at mRNA level. These data suggest that synthesis of MMPs and TIMP is a prolonged process and arterial SMC is a major source of MMP production in arterial neointima. Enhanced synthesis of MMPs and TIMPs at late stage of neointimal development may contribute to arterial ECM metabolism.

Animals↗
PubMed2001

Persistent postpartum urinary retention in contemporary obstetric practice. Definition, prevalence and clinical implications.

OBJECTIVE: To prospectively evaluate the prevalence, presumed etiologies and clinical implications of persistent postpartum urinary retention in modern obstetric practice. STUDY DESIGN: The study population comprised 8,402 consecutive, unselected parturients delivered in a university-affiliated maternity hospital over a one-year period. If a woman was unable to void spontaneously until the third postpartum day despite intermittent use of a Foley catheter, a diagnosis of persistent postpartum urinary retention was established. Patients were treated by insertion of a Foley catheter for up to two weeks and subsequently by a suprapubic catheter. Obstetric data were collected from the hospital records. RESULTS: Four patients (0.05% of the study population), aged 29-37 years, developed persistent postpartum urinary retention. Risk factors included vaginal delivery after cesarean section, prolonged second stage of labor, epidural analgesia, and delayed diagnosis and intervention. Urodynamic evaluation, performed on two patients one month after removal of the suprapubic catheter, revealed genuine stress incontinence in one and detrusor instability in another. None had had any lower urinary tract symptoms before pregnancy and delivery. CONCLUSION: Persistent postpartum urinary retention in contemporary obstetric practice is rare but may be associated with long-term bladder dysfunction. Early diagnosis and intervention are required to prevent irreversible bladder damage.

Adult↗
PubMed2000

Subharmonic resonances in plasmas: exponential and superexponential growth of driven relativistic plasma waves

Subharmonic resonant beat-wave excitation of nonlinear relativistic plasma waves is studied analytically and in particle-in-cell simulations. We find that if the frequency separation of the lasers, Deltaomega, is 2omega(p) or 3omega(p) ( omega(p) is the plasma frequency), then plasma waves are still excited at omega(p) but they grow exponentially or superexponentially rather than secularly. Both of these subharmonic resonant instabilities saturate due to relativistic detuning. The analytical growth rates and saturation levels agree with the simulation results.

Journal Article↗
PubMed2000

Significant evidence for linkage disequilibrium over a 5-cM region among Afrikaners.

We explore the extent of deviations from Hardy-Weinberg equilibrium (HWE) at a marker locus and linkage disequilibrium (LD) between pairs of marker loci in the Afrikaner population of South Africa. DNA samples were used for genotyping of 23 loci on six chromosomes. The samples were collected from 91 healthy unrelated Afrikaner adults. Exact tests were used to determine evidence for deviations from HWE at a single marker locus or LD between pairs of marker loci. At the 0.05 level of significance, evidence was found for deviation from HWE at only one of the 23 loci. At the same level of significance, LD was found among 8 of the 34 intrachromosomal pairs of loci. On chromosome 21, there was evidence for LD (P = 0.02) between a pair of loci with a genetic distance of 5.51 cM. On chromosome 2, there was evidence for LD between a pair of loci with a genetic distance of 5.28 cM (P = 0.002) and a pair of loci with a genetic distance of 3.68 cM (P = 0.0004). Detailed analysis of LD for one locus pair indicated that only a few of all alleles participated in the LD and that strong LD was most often positive. Our findings indicate that Afrikaans-speaking Afrikaners represent one of those special populations deemed particularly suitable for disequilibrium mapping.

Adult↗
PubMed2000

The use of prophylactic Stamey bladder neck suspension to prevent post-operative stress urinary incontinence in clinically continent women undergoing genitourinary prolapse repair.

The present study was undertaken to evaluate the efficacy of Stamey bladder neck suspension in preventing post-perative stress urinary incontinence in clinically continent women undergoing surgery for genitourinary prolapse. Thirty clinically continent women with severe genitourinary prolapse were found to have a positive stress test with re-positioning of the prolapse. They all had significant urethrovesical junction hypermobility. In addition to the genitourinary prolapse repair, these patients underwent a prophylactic Stamey procedure to prevent the possible development of post-operative stress urinary incontinence. The mean duration of follow-up was 8+/-4.5 months (range, 3-19 months). Seven (23.30%) patients developed overt post-operative stress urinary incontinence that was confirmed urodynamically. Eleven (36.7%) other patients denied stress incontinence; however, post-operative urodynamics demonstrated sphincteric incontinence. Post-operative complications were uncommon and minor. In conclusion, continent patients with a positive stress test demonstrated on re-positioning of the prolapse during pre-operative urodynamic evaluation are considered to be at high risk of developing post-operative stress urinary incontinence. In these patients, an additional, effective anti-incontinence procedure should be considered during surgical correction of genitourinary prolapse. The Stamey procedure, although simple and safe, does not appear to be the optimal solution to this clinical problem.

Aged↗
PubMed2000

Modulation of cloned skeletal muscle sodium channels by the scorpion toxins Lqh II, Lqh III, and Lqh alphaIT.

The scorpion alpha-toxins Lqh II, Lqh III, and Lqh alphaIT from Leiurus quinquestriatus hebraeus are representatives of typical alpha-toxins, specific for either mammals (Lqh II) or insects (Lqh alphaIT), and alpha-like toxins (Lqh III) which act on both mammals and insects. For a comparative study of the effects of these toxins on mammalian sodium channels we stably expressed rat skeletal muscle sodium channel alpha subunits (microI) in HEK 293 cells and measured Na+ currents in the whole-cell patch-clamp mode. The alpha- and alpha-like toxins strongly slowed down channel inactivation with a half-maximal effect at 1.4 nM (Lqh II), 5.4 nM (Lqh III), and 0.5 nM (Lqh alphaIT). The recovery from fast inactivation was accelerated by all toxins with the potency sequence: Lqh II>Lqh alphaIT>Lqh III. The voltage dependence of inactivation and recovery from inactivation were reduced while the threshold for activation was only slightly shifted by approximately equal to 10 mV without altering the slope factors, suggesting uncoupling of the impaired inactivation from the activation. The toxins induced an increase in peak inward current, which was accounted for by an increased maximal open-channel probability. Although all three toxins induced similar modifications of the channel properties, their kinetics of association and dissociation were very different. Between -140 and -80 mV toxin association was not voltage dependent. In 100 nM toxin the association time constants were: 1.3 s (Lqh II), 20 s (Lqh III), and 3.8 s (Lqh alphaIT). At positive voltages the toxin dissociated from the channel; at +100 mV the dissociation time constants were 30, 321, and 135 ms, respectively. In contrast to the association, dissociation was voltage dependent with a similar slope of about 12 mV per e-fold change for all three toxins. The strong differences in the association and dissociation kinetics of these toxins may identify them as members of different scorpion alpha-toxin subgroups.

Animals↗
PubMed2000

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